The main group of Digital Broadcast Tv stations/channels are to the , North East , East , with a smaller group to the North West.
Recommend put the HDTVi antenna in/at a North facing window and aim the antenna in the direction of ~ North East ~ the best you can.
If a Long coax running through the apartment is required to connect the HDTVi antenna to the Tv , Then So Be It.
Here is how to aim antennas ,
http://www.kyes.com/antenna/pointing/pointing.html.
Digital Tuners can develop - Digital Glitches - that are not cleared out with simple channel scans.
Do Double Rescan ,
http://www.wchstv.com/DoubleRescanAlert.pdf.
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